Microgravity Science and Technology最新文献

{"title":"Effect of Simulated Microgravity on Krüppel-Like Factor Expression in Gastrointestinal Cells of Aged Rats","authors":"Ahmed Al-Dwairi,&nbsp;Tayseer Afifi,&nbsp;Othman Al-Shboul,&nbsp;Abdulsalam Bani Hamad,&nbsp;Doa’a Al-u’datt","doi":"10.1007/s12217-026-10246-3","DOIUrl":"10.1007/s12217-026-10246-3","url":null,"abstract":"<div>\u0000 \u0000 <p>Microgravity alters gastrointestinal physiology, posing health risks during spaceflight. Krüppel-like factors (KLFs) are key transcriptional regulators of intestinal integrity, yet their behavior under microgravity in aged tissues remains unclear. Understanding these changes is vital for protecting gut health in aging individuals exposed to such environments. This study aimed to determine the effect of simulated microgravity on mRNA expression of KLFs in small intestine and colon cells and smooth muscles. This study employed a hindlimb unloading model to simulate microgravity conditions in laboratory-aged rats. A total of 15 male Sprague Dawley rats, aged 18–24 months, were divided into control (<i>n</i> = 7) and suspended (<i>n</i> = 8) groups, with suspension being induced for a period of two weeks. Following the intervention, small intestine and colon tissues were harvested for molecular analysis. Gene expression levels of KLFs (4, 5, 6 and 9) were quantitatively assessed using real-time reverse transcription polymerase chain reaction (RT-qPCR). Immunohistochemistry was employed to detect and quantify KLFs expression patterns. Significant morphological and molecular alterations were observed in intestinal tissues under simulated microgravity. Hindlimb suspension resulted in a pronounced reduction in small intestinal villus length (<i>P</i> &lt; 0.0001) and a marked decrease in Paneth cell count (<i>P</i> &lt; 0.0001). Gene expression analysis revealed tissue-specific modulation of Krüppel-like factors (KLFs). In the small intestine, KLF6 expression significantly declined (<i>P</i> = 0.047), while KLF9 levels increased (<i>P</i> = 0.035). In small intestinal smooth muscle, KLF5 was significantly downregulated (<i>P</i> = 0.009). Conversely, colonic smooth muscle exhibited significant upregulation of KLF4 (<i>P</i> = 0.032) and KLF5 (<i>P</i> &lt; 0.001), alongside a significant reduction in KLF9 (<i>P</i> = 0.021). This study highlighted the impact of simulated microgravity, via hindlimb suspension, on intestinal structure and KLF gene expression in aged rats. Villus length was significantly reduced, indicating impaired absorptive function, while Paneth cell depletion suggests weakened mucosal immunity. Although changes in crypt depth and muscle thickness were minimal, molecular analysis showed downregulation of KLF6 and upregulation of KLF9, pointing to disrupted epithelial homeostasis. KLF4 and KLF5 levels remained stable at the mRNA level.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential Gene Expression of Acidovorax sp.1,608,163 under Simulated Microgravity","authors":"Eduardo Jacobo Gutierrez,&nbsp;Madhusudan Choudhary,&nbsp;Alexis Ho,&nbsp;Anand B. Karki","doi":"10.1007/s12217-026-10245-4","DOIUrl":"10.1007/s12217-026-10245-4","url":null,"abstract":"<div>\u0000 \u0000 <p>Previous studies reported that microorganisms, including several bacterial species, under microgravity stress undergo differential gene expression leading to diverse physiological responses such as increased growth, virulence, antibiotic resistance, and biofilm production. This study examines the gene-expression differences of <i>Acidovorax sp</i>. 1,608,163 under normal and simulated microgravity conditions. Strains of the <i>Acidovorax species</i> are free-living, environmental commensals, plant or human opportunistic pathogens that can infect a variety of crops, including corn, rice, oats, and wheat. The hypothesis that “<i>Acidovorax</i> grown under microgravity alters the gene expression patterns” is tested by comparing transcriptomic data of bacterial cultures at the log (42 h) and stationary (72 h) phases grown under normal and microgravity conditions. Total RNA was extracted and reverse transcribed, and then the cDNA was sequenced using the Illumina HiSeq 4000 platform. Results revealed the difference in growth rates, which were significantly higher under microgravity conditions than under normal gravity conditions. Of the total of 678 differentially expressed genes, 232 (34.22%) and 446 (65.78%) genes were up- and down-regulated in the log phase, respectively, whereas the total of 231 differentially expressed genes at the stationary phase, 32 (13.85%) and 199 (86.15%) genes were up- and down-regulated, respectively. Furthermore, results also indicated that genes coding for several COGs functions, especially in metabolism, signal-transduction, transcription, translation, chemotaxis, and cell motility, were down-regulated in response to microgravity stress, and therefore, the downregulation of genes seems to be the central mechanism for cells to cope under stimulated microgravity.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12217-026-10245-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GRS Ground-Based Short-Term Microgravity Test of “Taiji-1” Utilizing the µg0-Level Drop Tower Beijing","authors":"Laifu Chen,&nbsp;Shaoxin Wang,&nbsp;Kai Li,&nbsp;Jianfu Zhao,&nbsp;Heng Jiang,&nbsp;Zuolei Wang,&nbsp;Ziren Luo,&nbsp;Keqi Qi,&nbsp;Ruihong Gao","doi":"10.1007/s12217-026-10244-5","DOIUrl":"10.1007/s12217-026-10244-5","url":null,"abstract":"<div>\u0000 \u0000 <p>The drop tower facility generates a ground-based microgravity environment, functioning as a validation platform for a wide range of microgravity scientific experiments. To satisfy the ultra-low microgravity requirements for ground testing of the Gravitational Reference Sensor (GRS)—the core payload of the “Taiji-1” mission—a newly designed experimental capsule was developed for the Drop Tower Beijing (DTB). Using this capsule, successful tests were conducted on the GRS engineering model. Experimental results show that the Test Mass (TM) is stably captured during the effective microgravity period, achieving a control precision better than 1 × 10⁻⁶ <i>g</i>₀/Hz^1/2 across the 1–50 Hz frequency band. Collectively, these results validate both the capture and control performance of the GRS and the capability of the DTB with the newly designed dual-cell capsule to provide a µ<i>g</i>₀-level microgravity environment. This successful verification provides strong support for future scientific experiments demanding ultra-high microgravity level.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Rotation and Variable Viscosity on Convective Instability in a Navier–Stokes–Voigt Fluid Layer","authors":"Dhananjay Yadav,&nbsp;Mukesh Kumar Awasthi,&nbsp;Ravi Ragoju,&nbsp;Raghunath Kodi,&nbsp;Amit Mahajan","doi":"10.1007/s12217-025-10228-x","DOIUrl":"10.1007/s12217-025-10228-x","url":null,"abstract":"<div>\u0000 \u0000 <p>This investigation analyzes the effects of variable viscosity and rotation on the onset of thermal convection in a non-Newtonian Navier–Stokes–Voigt (NSV) fluid, which has not been addressed in the available literature. The threshold for convective instability is obtained by linearizing the governing equations related to the perturbations. The consequential eigenvalue problem is then solved both analytically and numerically through the Galerkin process. The necessity of the Kelvin-Voigt factor, the viscosity variation factor, the Taylor number and the Prandtl number on the critical stability parameters is exhaustively examined. It is detected that above the certain threshold assessment of the Taylor number, the instability creates in as oscillatory type. The threshold range of the Taylor number at which oscillatory motion probable enhances with increasing the viscosity variation factor while, it declines with increasing the Prandtl number. The stability of the arrangement increases with increasing the Taylor number and the Prandtl number whereas, it decreases with the viscosity variation factor and the Kelvin-Voigt factor. The dimension of the convective cells declines with increasing the Taylor number, the viscosity variation factor and the Prandtl number while, it upsurges with the Kelvin-Voigt factor if the value of the Prandtl number is more than one.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Simulated Microgravity on Osseointegration of Titanium Implants and the Interventional Role of Icariin Combined with Exercise","authors":"Hong-zhi Zhou,&nbsp;Wen-tian Wang,&nbsp;An-qing Wang,&nbsp;Su-meng Shi,&nbsp;Yu-wei Zhang,&nbsp;Xue-ling Wang","doi":"10.1007/s12217-026-10243-6","DOIUrl":"10.1007/s12217-026-10243-6","url":null,"abstract":"<div>\u0000 \u0000 <p>This study investigated the impact of simulated microgravity on titanium implant osseointegration and assessed the reparative efficacy of icariin (ICA) combined with treadmill exercise. Male Sprague–Dawley rats (<i>n</i> = 24) were divided into four groups: normal gravity control (CON), simulated microgravity (SMG), SMG + ICA, and SMG + ICA+treadmill exercise (SMG + ICA+EXER). SMG groups underwent tail suspension for four weeks, followed by ICA (25 mg/kg/day) and/or exercise interventions. Micro-CT, fluorochrome labeling, toluidine blue staining, and biomechanical tests were performed at week 8. Micro-CT analysis revealed that Groups SMG, SMG + ICA, and SMG + ICA+EXER exhibited a gradual increase in Tb.Th, Tb.BV/TV, DA, Tb.BMD, and Tb.BMC, and a gradual decrease in BS/BV, Tb.Sp, and SMI compared to Group CON, Mineral apposition rate (MAR) and bone-to-implant contact (BIC) were also significantly higher in ICA groups ( <i>P</i> &lt; 0.05 ), matching CON levels ( <i>P</i> &gt; 0.05 ). Biomechanical strength was enhanced in ICA groups, with superior performance in SMG + ICA+EXER. Simulated microgravity impairs osseointegration, but ICA mitigates these effects, with treadmill exercise further augmenting bone integration and biomechanical strength. This combined strategy may serve as a viable countermeasure for maintaining implant stability in space medicine.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12217-026-10243-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of Heat Transfer in Solidification Experiments of Lightweight High-entropy Alloys on Chinese Space Station","authors":"Pengfei Lu,&nbsp;Rui Liu,&nbsp;Lubin Wang,&nbsp;Qiang Yu","doi":"10.1007/s12217-025-10230-3","DOIUrl":"10.1007/s12217-025-10230-3","url":null,"abstract":"<div>\u0000 \u0000 <p>Owing to the difference in convective heat transfer mechanisms between space and ground, the temperature profile of lightweight high-entropy alloys (HEAs) in space is different from the ground which may prevent the samples from melting as intended and thus cause the space experiment to fail. To predict the temperature profile and obtain the heat transfer characteristics in space, it employed experimental temperature data of the standard SCA at 800 °C under both ground and space. Specifically, numerical models of the high-temperature furnace and SCA were established, and different operating conditions and relevant thermophysical parameters were adjusted to conduct the thermal simulations of the temperature profile of the SCA in space and on ground. The respective heat transfer characteristics for space and ground were thus obtained. Based on the obtained heat transfer characteristics, the temperature profile and heat transfer characteristics of the lightweight HEA experiment in space were predicted when the furnace temperature is 900 °C, the target experimental temperature from the ground-based HEA experiment. The results provide an important foundation for conducting HEA solidification experiments in microgravity.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D Spatiotemporal Oscillation Characteristics of Nanofluids Thermocapillary Convection in Rectangular Cavity","authors":"Yanni Jiang,&nbsp;Yuhang Zheng,&nbsp;Cheng Dai,&nbsp;Xiaoming Zhou","doi":"10.1007/s12217-025-10232-1","DOIUrl":"10.1007/s12217-025-10232-1","url":null,"abstract":"<div><p>For disclose the 3D spatiotemporal oscillation characteristics of nanofluid thermocapillary convection, this paper numerically studies the supercritical oscillatory process of nanofluids thermocapillary convection in a 3D rectangular cavity under microgravity conditions, and the propagation characteristics of flow field and temperature waves are analyzed. The results show that, under supercritical condition the flow field is composed of multiple dynamically migrating convective vortices, and the periodic temperature waves not only appear at free surface, but also inside the liquid layer. With increasing nanoparticle volume fraction, both the dominant frequency and amplitude of velocity oscillation exhibit linear reduction, while the oscillation period increases linearly. Furthermore, the propagation angle of hydrothermal waves increases progressively with nanoparticles volume fraction increasing, particularly, the angle from 27.5° increases to 33° as nanoparticles volume fraction varies from 0 to 0.05.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concentration-Induced Convection in Reactive Wetting of Al–Mg-Mn Alloys by Zn-based Solders under Variable Gravity","authors":"Svetlana A. Gruzd,&nbsp;Ilya R. Saltykov,&nbsp;Ilya V. Shutov,&nbsp;Dmitry S. Samsonov,&nbsp;Mikhail D. Krivilyov","doi":"10.1007/s12217-026-10237-4","DOIUrl":"10.1007/s12217-026-10237-4","url":null,"abstract":"<div><p>Brazing of aluminum alloys using chemically active fillers is in demand in transportation and aerospace engineering for the development of new techniques suitable under microgravity conditions for outer space repair. This work presents a theoretical study of diffusion and hydrodynamic flows in molten Zn solder during the reactive wetting of an Al–Mg-Mn plate under various gravity conditions. The model is developed in the isothermal formulation at different wetting temperatures, considering the concentration-driven effect in the soldered zone. The influence of Marangoni convection caused by the Zn concentration gradient on the flow structure and erosion of the base material is analyzed. The effect of zinc evaporation during reactive wetting under vacuum conditions is revealed and quantitatively described. The dependency of the Zn solder droplet radius during its spreading on a flat Al–Mg-Mn plate under various external conditions is also analyzed.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147363364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunological and Hormonal Changes During a 25‑h Shallow‑Water Immersion: a Two‑Case Report","authors":"Luca Bonanni,&nbsp;Gino Chioetto,&nbsp;Nicola Ferri","doi":"10.1007/s12217-026-10236-5","DOIUrl":"10.1007/s12217-026-10236-5","url":null,"abstract":"<div>\u0000 \u0000 <p>Prolonged immersion in thermoneutral water reproduces several physiological adaptations of orbital flight but its endocrine‑immune consequences remain incompletely characterised. We investigated stress hormones and immune markers in two healthy divers undergoing a 25‑h shallow‑water immersion and compared the findings with contemporary microgravity literature. Peripheral blood was collected one day before and &lt; 15 min after immersion. Flow cytometry, 51Cr‑release assay, lymphocyte proliferation, intracellular cytokine PCR and routine endocrinology panels were performed. All data were corrected for plasma‑volume shifts. Cortisol, growth hormone and prolactin increased by 45–100%, whereas testosterone declined modestly. CD56⁺ natural killer (NK)‑cell frequency fell (‑25% and ‑32%) without loss of cytotoxicity. PBMC proliferation in response to phytohaemagglutinin decreased (‑30% to ‑45%). A Th1 → Th2 cytokine shift was evident with lower IFN‑γ and higher IL‑4 expression. These responses mirror patterns reported after head‑down bed rest and long‑duration spaceflight. Extended shallow‑water immersion is sufficient to activate the neuro‑endocrine stress axis and induce selective, microgravity‑like immune alterations. Thermoneutral immersion may therefore serve as a cost‑effective analogue for mechanistic studies and countermeasure testing.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147342432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microhemodynamic Adjustments and the Type of Autonomic Regulation Under Analog Long-term Isolation Conditions","authors":"D. V. Pashkova,&nbsp;O. V. Popova,&nbsp;J. A. Popova,&nbsp;Yu I. Loktionova,&nbsp;E. V. Zharkikh,&nbsp;V. V. Sidorov,&nbsp;A. V. Dunaev,&nbsp;V. B. Rusanov","doi":"10.1007/s12217-026-10241-8","DOIUrl":"10.1007/s12217-026-10241-8","url":null,"abstract":"<div>\u0000 \u0000 <p>This study focused on microhemodynamic and autonomic regulation changes during long-term isolation in a 366-day SIRIUS-23 experiment with 6 healthy volunteers (2 men and 4 women, aged 25–37 years). Heart rate variability analysis and laser Doppler flowmetry were used to assess cardiovascular system responses before, during, and after isolation. Volunteers demonstrated distinct autonomic regulation patterns, dividing into two groups based on vagal tone and vascular center activity. Group 2 showed consistently higher autonomic function throughout the experiment. Microcirculation parameters revealed decreased perfusion in the forehead area for Group 1 and fluctuating dynamics for Group 2. Both groups exhibited endothelial tone reduction and altered blood flow distribution in the toe area with increased shunt flow. Prolonged isolation significantly affects microhemodynamics and autonomic regulation. Individuals with higher vagal tone demonstrated better adaptation. These findings contribute to understanding physiological responses to long-term confinement and have implications for space mission medical support.</p>\u0000 </div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"38 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147342431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}